Vacuum adiabatic body and refrigerator

ABSTRACT

A vacuum adiabatic body may include: a first plate member; a second plate member; a sealing part sealing the first plate member and the second plate member to provide a third space; a supporting unit maintaining the third space; a heat resistance unit at least including a conductive resistance sheet capable of resisting heat conduction flowing along a wall for the third space to decrease a heat transfer amount between the first plate member and the second plate member; and an exhaust port through which a gas in the third space is exhausted. A side frame may be fastened to the conductive resistance sheet and the second plate member, and the side frame is fastened to an edge portion of the second plate member. Accordingly, the formation of dews may be prevented and an adiabatic effect may be improved.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Divisional Application of U.S. National Stage application Ser. No. 15/749,139, filed Jan. 31, 2018 under 35 U.S.C. § 371 of PCT Application No. PCT/KR2016/008502, filed Aug. 2, 2016, which claims priority to Korean Patent Application No. 10-2015-0109723, filed Aug. 3, 2015, whose entire disclosures are hereby incorporated by reference.

BACKGROUND 1. Field

The present disclosure relates to a vacuum adiabatic body and a refrigerator.

2. Background

A vacuum adiabatic body is a product for suppressing heat transfer by vacuumizing the interior of a body thereof. The vacuum adiabatic body can reduce heat transfer by convection and conduction, and hence is applied to heating apparatuses and refrigerating apparatuses. In a typical adiabatic method applied to a refrigerator, although it is differently applied in refrigeration and freezing, a foam urethane adiabatic wall having a thickness of about 30 cm or more is generally provided. However, the internal volume of the refrigerator is therefore reduced.

In order to increase the internal volume of a refrigerator, there is an attempt to apply a vacuum adiabatic body to the refrigerator.

First, Korean Patent No. 10-0343719 (Reference Document 1) of the present applicant has been disclosed. According to Reference Document 1, there is disclosed a method in which a vacuum adiabatic panel is prepared and then built in walls of a refrigerator, and the exterior of the vacuum adiabatic panel is finished with a separate molding as Styrofoam (polystyrene). According to the method, additional foaming is not required, and the adiabatic performance of the refrigerator is improved. However, manufacturing cost is increased, and a manufacturing method is complicated. As another example, a technique of providing walls using a vacuum adiabatic material and additionally providing adiabatic walls using a foam filling material has been disclosed in Korean Patent Publication No. 10-2015-0012712 (Reference Document 2). According to Reference Document 2, manufacturing cost is increased, and a manufacturing method is complicated.

As another example, there is an attempt to manufacture all walls of a refrigerator using a vacuum adiabatic body that is a single product. For example, a technique of providing an adiabatic structure of a refrigerator to be in a vacuum state has been disclosed in U.S. Patent Laid-Open Publication No. US 2004/0226956 A1 (Reference Document 3).

BRIEF DESCRIPTION OF THE DRAWINGS

The embodiments will be described in detail with reference to the following drawings in which like reference numerals refer to like elements wherein:

The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

FIG. 1 is a perspective view of a refrigerator according to an embodiment.

FIG. 2 is a view schematically showing a vacuum adiabatic body used in a main body and a door of the refrigerator.

FIG. 3 is a view showing various embodiments of an internal configuration of a vacuum space part.

FIG. 4 is a view showing various embodiments of conductive resistance sheets and peripheral parts thereof.

FIG. 5 is a view illustrating in detail a vacuum adiabatic body according to an embodiment.

FIG. 6 illustrates temperature distribution curves with respect to positions of a conductive resistance sheet.

FIG. 7 is an exploded perspective view of a vacuum adiabatic body according to an embodiment.

FIG. 8 illustrates graphs showing changes in adiabatic performance and changes in gas conductivity with respect to vacuum pressures by applying a simulation.

FIG. 9 illustrates graphs obtained by observing, over time and pressure, a process of exhausting the interior of the vacuum adiabatic body when a supporting unit is used.

FIG. 10 illustrates graphs obtained by comparing vacuum pressures and gas conductivities.

FIG. 11 is a partial sectional view of a vacuum adiabatic body according to an embodiment.

FIG. 12 is a view comparing volume performances of an external door of a door-in-door refrigerator.

DETAILED DESCRIPTION

Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings.

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific preferred embodiments in which the disclosure may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is understood that other embodiments may be utilized and that logical structural, mechanical, electrical, and chemical changes may be made without departing from the spirit or scope of the disclosure. To avoid detail not necessary to enable those skilled in the art to practice the disclosure, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense.

In the following description, the term ‘vacuum pressure’ means a certain pressure state lower than atmospheric pressure. In addition, the expression that a vacuum degree of A is higher than that of B means that a vacuum pressure of A is lower than that of B.

FIG. 1 is a perspective view of a refrigerator according to an embodiment.

Referring to FIG. 1 , the refrigerator 1 includes a main body 2 provided with a cavity 9 capable of storing storage goods and a door 3 provided to open/close the main body 2. The door 3 may be rotatably or movably disposed to open/close the cavity 9. The cavity 9 may provide at least one of a refrigerating chamber and a freezing chamber.

Parts constituting a freezing cycle in which cold air is supplied into the cavity 9. Specifically, the parts include a compressor 4 for compressing a refrigerant, a condenser 5 for condensing the compressed refrigerant, an expander 6 for expanding the condensed refrigerant, and an evaporator 7 for evaporating the expanded refrigerant to take heat. As a typical structure, a fan may be installed at a position adjacent to the evaporator 7, and a fluid blown from the fan may pass through the evaporator 7 and then be blown into the cavity 9. A freezing load is controlled by adjusting the blowing amount and blowing direction by the fan, adjusting the amount of a circulated refrigerant, or adjusting the compression rate of the compressor, so that it is possible to control a refrigerating space or a freezing space.

FIG. 2 is a view schematically showing a vacuum adiabatic body used in the main body and the door of the refrigerator. In FIG. 2 , a main body-side vacuum adiabatic body is illustrated in a state in which top and side walls are removed, and a door-side vacuum adiabatic body is illustrated in a state in which a portion of a front wall is removed. In addition, sections of portions at conductive resistance sheets are provided are schematically illustrated for convenience of understanding.

Referring to FIG. 2 , the vacuum adiabatic body includes a first plate member (or first plate) 10 for providing a wall of a low-temperature space, a second plate member (or second plate) 20 for providing a wall of a high-temperature space, a vacuum space part (or vacuum space or cavity) 50 defined as a gap part (or gap or space) between the first and second plate members 10 and 20. Also, the vacuum adiabatic body includes the conductive resistance sheets 60 and 63 for preventing heat conduction between the first and second plate members 10 and 20. A sealing part (or seal or sealing joint) 61 for sealing the first and second plate members 10 and 20 is provided such that the vacuum space part 50 is in a sealing state. When the vacuum adiabatic body is applied to a refrigerating or heating cabinet, the first plate member 10 may be referred to as an inner case, and the second plate member 20 may be referred to as an outer case. A machine chamber 8 in which parts providing a freezing cycle are accommodated is placed at a lower rear side of the main body-side vacuum adiabatic body, and an exhaust port 40 for forming a vacuum state by exhausting air in the vacuum space part 50 is provided at any one side of the vacuum adiabatic body. In addition, a pipeline 64 passing through the vacuum space part 50 may be further installed so as to install a defrosting water line and electric lines.

The first plate member 10 may define at least one portion of a wall for a first space provided thereto. The second plate member 20 may define at least one portion of a wall for a second space provided thereto. The first space and the second space may be defined as spaces having different temperatures. Here, the wall for each space may serve as not only a wall directly contacting the space but also a wall not contacting the space. For example, the vacuum adiabatic body of the embodiment may also be applied to a product further having a separate wall contacting each space.

Factors of heat transfer, which cause loss of the adiabatic effect of the vacuum adiabatic body, are heat conduction between the first and second plate members 10 and 20, heat radiation between the first and second plate members 10 and 20, and gas conduction of the vacuum space part 50.

Hereinafter, a heat resistance unit provided to reduce adiabatic loss related to the factors of the heat transfer will be provided. The heat resistance unit may also be referred to as a thermal insulator, or the like, that provides one or more structural means configured to provide thermal insulation. Meanwhile, the vacuum adiabatic body and the refrigerator of the embodiment do not exclude that another adiabatic means is further provided to at least one side of the vacuum adiabatic body. Therefore, an adiabatic means using foaming or the like may be further provided to another side of the vacuum adiabatic body.

FIG. 3 is a view showing various embodiments of an internal configuration of the vacuum space part.

First, referring to FIG. 3 a , the vacuum space part 50 is provided in a third space having a different pressure from the first and second spaces, preferably, a vacuum state, thereby reducing adiabatic loss. The third space may be provided at a temperature between the temperature of the first space and the temperature of the second space. Since the third space is provided as a space in the vacuum state, the first and second plate members 10 and 20 receive a force contracting in a direction in which they approach each other due to a force corresponding to a pressure difference between the first and second spaces. Therefore, the vacuum space part 50 may be deformed in a direction in which it is reduced. In this case, adiabatic loss may be caused due to an increase in amount of heat radiation, caused by the contraction of the vacuum space part 50, and an increase in amount of heat conduction, caused by contact between the plate members 10 and 20.

A supporting unit (support) 30 may be provided to reduce the deformation of the vacuum space part 50. The supporting unit 30 includes bars 31. The bars 31 may extend in a direction substantially vertical to the first and second plate members 10 and 20 so as to support a distance between the first and second plate members 10 and 20. A support plate 35 may be additionally provided to at least one end of the bar 31. The support plate 35 connects at least two bars 31 to each other, and may extend in a direction horizontal to the first and second plate members 10 and 20. The support plate 35 may be provided in a plate shape, or may be provided in a lattice shape such that its area contacting the first or second plate member 10 or 20 is decreased, thereby reducing heat transfer. The bars 31 and the support plate 35 are fixed to each other at at least one portion, to be inserted together between the first and second plate members 10 and 20. The support plate 35 contacts at least one of the first and second plate members 10 and 20, thereby preventing deformation of the first and second plate members 10 and 20. In addition, based on the extending direction of the bars 31, a total sectional area of the support plate 35 is provided to be greater than that of the bars 31, so that heat transferred through the bars 31 can be diffused through the support plate 35.

A material of the supporting unit 30 may include a resin selected from the group consisting of PC, glass fiber PC, low outgassing PC, PPS, and LCP so as to obtain high compressive strength, low outgassing and water absorptance, low thermal conductivity, high compressive strength at high temperature, and excellent machinability.

A radiation resistance sheet 32 for reducing heat radiation between the first and second plate members 10 and 20 through the vacuum space part 50 will be described. The first and second plate members 10 and 20 may be made of a stainless material capable of preventing corrosion and providing a sufficient strength. The stainless material has a relatively high emissivity of 0.16, and hence a large amount of radiation heat may be transferred. In addition, the supporting unit 30 made of the resin has a lower emissivity than the plate members, and is not entirely provided to inner surfaces of the first and second plate members 10 and 20. Hence, the supporting unit 30 does not have great influence on radiation heat. Therefore, the radiation resistance sheet 32 may be provided in a plate shape over a majority of the area of the vacuum space part 50 so as to concentrate on reduction of radiation heat transferred between the first and second plate members 10 and 20. A product having a low emissivity may be preferably used as the material of the radiation resistance sheet 32. In an embodiment, an aluminum foil having an emissivity of 0.02 may be used as the radiation resistance sheet 32. Since the transfer of radiation heat cannot be sufficiently blocked using one radiation resistance sheet, at least two radiation resistance sheets 32 may be provided at a certain distance so as not to contact each other. In addition, at least one radiation resistance sheet may be provided in a state in which it contacts the inner surface of the first or second plate member 10 or 20.

Referring to FIG. 3 b , the distance between the plate members is maintained by the supporting unit 30, and a porous material 33 may be filled in the vacuum space part 50. The porous material 33 may have a higher emissivity than the stainless material of the first and second plate members 10 and 20. However, since the porous material 33 is filled in the vacuum space part 50, the porous material 33 has a high efficiency for resisting the radiation heat transfer.

In this embodiment, the vacuum adiabatic body can be manufactured without using the radiation resistance sheet 32.

Referring to FIG. 3 c , the supporting unit 30 maintaining the vacuum space part 50 is not provided. Instead of the supporting unit 30, the porous material 33 is provided in a state in which it is surrounded by a film 34. In this case, the porous material 33 may be provided in a state in which it is compressed so as to maintain the gap of the vacuum space part 50. The film 34 is made of, for example, a PE material, and may be provided in a state in which holes are formed therein.

In this embodiment, the vacuum adiabatic body can be manufactured without using the supporting unit 30. In other words, the porous material 33 can serve together as the radiation resistance sheet 32 and the supporting unit 30.

FIG. 4 is a view showing various embodiments of the conductive resistance sheets and peripheral parts thereof. Structures of the conductive resistance sheets are briefly illustrated in FIG. 2 , but will be understood in detail with reference to FIG. 4 .

First, a conductive resistance sheet proposed in FIG. 4 a may be preferably applied to the main body-side vacuum adiabatic body. Specifically, the first and second plate members 10 and 20 are to be sealed so as to vacuumize the interior of the vacuum adiabatic body. In this case, since the two plate members have different temperatures from each other, heat transfer may occur between the two plate members. A conductive resistance sheet 60 is provided to prevent heat conduction between two different kinds of plate members.

The conductive resistance sheet 60 may be provided with sealing parts 61 at which both ends of the conductive resistance sheet 60 are sealed to define at least one portion of the wall for the third space and maintain the vacuum state. The conductive resistance sheet 60 may be provided as a thin foil in units of micrometers so as to reduce the amount of heat conducted along the wall for the third space. The sealing parts 61 may be provided as welding parts. That is, the conductive resistance sheet 60 and the plate members 10 and 20 may be fused to each other. In order to cause a fusing action between the conductive resistance sheet 60 and the plate members 10 and 20, the conductive resistance sheet 60 and the plate members 10 and 20 may be made of the same material, and a stainless material may be used as the material. The sealing parts 61 are not limited to the welding parts, and may be provided through a process such as cocking. The conductive resistance sheet 60 may be provided in a curved shape. Thus, a heat conduction distance of the conductive resistance sheet 60 is provided longer than the linear distance of each plate member, so that the amount of heat conduction can be further reduced.

A change in temperature occurs along the conductive resistance sheet 60. Therefore, in order to block heat transfer to the exterior of the conductive resistance sheet 60, a shielding part (shield) 62 may be provided at the exterior of the conductive resistance sheet 60 such that an adiabatic action occurs. In other words, in the refrigerator, the second plate member 20 has a high temperature and the first plate member 10 has a low temperature. In addition, heat conduction from high temperature to low temperature occurs in the conductive resistance sheet 60, and hence the temperature of the conductive resistance sheet 60 is suddenly changed. Therefore, when the conductive resistance sheet 60 is opened to the exterior thereof, heat transfer through the opened place may seriously occur. In order to reduce heat loss, the shielding part 62 is provided at the exterior of the conductive resistance sheet 60. For example, when the conductive resistance sheet 60 is exposed to any one of the low-temperature space and the high-temperature space, the conductive resistance sheet 60 does not serve as a conductive resistor as well as the exposed portion thereof, which is not preferable.

The shielding part 62 may be provided as a porous material contacting an outer surface of the conductive resistance sheet 60. The shielding part 62 may be provided as an adiabatic structure, e.g., a separate gasket, which is placed at the exterior of the conductive resistance sheet 60. The shielding part 62 may be provided as a portion of the vacuum adiabatic body, which is provided at a position facing a corresponding conductive resistance sheet 60 when the main body-side vacuum adiabatic body is closed with respect to the door-side vacuum adiabatic body. In order to reduce heat loss even when the main body and the door are opened, the shielding part 62 may be preferably provided as a porous material or a separate adiabatic structure.

A conductive resistance sheet proposed in FIG. 4 b may be preferably applied to the door-side vacuum adiabatic body. In FIG. 4 b , portions different from those of FIG. 4 a are described in detail, and the same description is applied to portions identical to those of FIG. 4 a . A side frame 70 is further provided at an outside of the conductive resistance sheet 60. A part for sealing between the door and the main body, an exhaust port necessary for an exhaust process, a getter port for vacuum maintenance, and the like may be placed on the side frame 70. This is because the mounting of parts is convenient in the main body-side vacuum adiabatic body, but the mounting positions of parts are limited in the door-side vacuum adiabatic body.

In the door-side vacuum adiabatic body, it is difficult to place the conductive resistance sheet 60 at a front end portion of the vacuum space part, i.e., a corner side portion of the vacuum space part. This is because, unlike the main body, a corner edge portion of the door is exposed to the exterior. More specifically, if the conductive resistance sheet 60 is placed at the front end portion of the vacuum space part, the corner edge portion of the door is exposed to the exterior, and hence there is a disadvantage in that a separate adiabatic part should be configured so as to heat-insulate the conductive resistance sheet 60.

A conductive resistance sheet proposed in FIG. 4 c may be preferably installed in the pipeline passing through the vacuum space part. In FIG. 4 c , portions different from those of FIGS. 4 a and 4 b are described in detail, and the same description is applied to portions identical to those of FIGS. 4 a and 4 b . A conductive resistance sheet having the same shape as that of FIG. 4 a , preferably, a wrinkled conductive resistance sheet 63 (or folded conductive resistance sheet) may be provided at a peripheral portion of the pipeline 64. Accordingly, a heat transfer path can be lengthened, and deformation caused by a pressure difference can be prevented. In addition, a separate shielding part may be provided to improve the adiabatic performance of the conductive resistance sheet.

A heat transfer path between the first and second plate members 10 and 20 will be described with reference back to FIG. 4 a . Heat passing through the vacuum adiabatic body may be divided into surface conduction heat {circle around (1)} conducted along a surface of the vacuum adiabatic body, more specifically, the conductive resistance sheet 60, supporter conduction heat {circle around (2)} conducted along the supporting unit 30 provided inside the vacuum adiabatic body, gas conduction heat (convection) {circle around (3)} conducted through an internal gas in the vacuum space part, and radiation transfer heat {circle around (4)} transferred through the vacuum space part.

The transfer heat may be changed depending on various depending on various design dimensions. For example, the supporting unit may be changed such that the first and second plate members 10 and 20 can endure a vacuum pressure without being deformed, the vacuum pressure may be changed, the distance between the plate members may be changed, and the length of the conductive resistance sheet may be changed. The transfer heat may be changed depending on a difference in temperature between the spaces (the first and second spaces) respectively provided by the plate members. In the embodiment, a preferred configuration of the vacuum adiabatic body has been found by considering that its total heat transfer amount is smaller than that of a typical adiabatic structure formed by foaming polyurethane. In a typical refrigerator including the adiabatic structure formed by foaming the polyurethane, an effective heat transfer coefficient may be proposed as 19.6 mW/mK.

By performing a relative analysis on heat transfer amounts of the vacuum adiabatic body of the embodiment, a heat transfer amount by the gas conduction heat {circle around (3)} can become smallest. For example, the heat transfer amount by the gas conduction heat {circle around (3)} may be controlled to be equal to or smaller than 4% of the total heat transfer amount. A heat transfer amount by solid conduction heat defined as a sum of the surface conduction heat {circle around (1)} and the supporter conduction heat {circle around (2)} is largest. For example, the heat transfer amount by the solid conduction heat may reach 75% of the total heat transfer amount. A heat transfer amount by the radiation transfer heat {circle around (4)} is smaller than the heat transfer amount by the solid conduction heat but larger than the heat transfer amount of the gas conduction heat {circle around (3)}. For example, the heat transfer amount by the radiation transfer heat {circle around (4)} may occupy about 20% of the total heat transfer amount.

According to such a heat transfer distribution, effective heat transfer coefficients (eK: effective K) (W/mK) of the surface conduction heat {circle around (1)}, the supporter conduction heat {circle around (2)}, the gas conduction heat {circle around (3)}, and the radiation transfer heat {circle around (4)} may have an order of Equation 1. eK_(solid conduction heat)>eK_(radiation transfer heat)>eK_(gas conduction heal)  Equation 1

Here, the effective heat transfer coefficient (eK) is a value that can be measured using a shape and temperature differences of a target product. The effective heat transfer coefficient (eK) is a value that can be obtained by measuring a total heat transfer amount and a temperature at least one portion at which heat is transferred. For example, a calorific value (W) is measured using a heating source that can be quantitatively measured in the refrigerator, a temperature distribution (K) of the door is measured using heat respectively transferred through a main body and an edge of the door of the refrigerator, and a path through which heat is transferred is calculated as a conversion value (m), thereby evaluating an effective heat transfer coefficient.

The effective heat transfer coefficient (eK) of the entire vacuum adiabatic body is a value given by k=QL/AΔT. Here, Q denotes a calorific value (W) and may be obtained using a calorific value of a heater. A denotes a sectional area (m²) of the vacuum adiabatic body, L denotes a thickness (m) of the vacuum adiabatic body, and ΔT denotes a temperature difference.

For the surface conduction heat, a conductive calorific value may be obtained through a temperature difference (ΔT) between an entrance and an exit of the conductive resistance sheet 60 or 63, a sectional area (A) of the conductive resistance sheet, a length (L) of the conductive resistance sheet, and a thermal conductivity (k) of the conductive resistance sheet (the thermal conductivity of the conductive resistance sheet is a material property of a material and can be obtained in advance). For the supporter conduction heat, a conductive calorific value may be obtained through a temperature difference (ΔT) between an entrance and an exit of the supporting unit 30, a sectional area (A) of the supporting unit, a length (L) of the supporting unit, and a thermal conductivity (k) of the supporting unit. Here, the thermal conductivity of the supporting unit is a material property of a material and can be obtained in advance. The sum of the gas conduction heat {circle around (3)}, and the radiation transfer heat {circle around (4)} may be obtained by subtracting the surface conduction heat and the supporter conduction heat from the heat transfer amount of the entire vacuum adiabatic body. A ratio of the gas conduction heat {circle around (3)}, and the radiation transfer heat {circle around (4)} may be obtained by evaluating radiation transfer heat when no gas conduction heat exists by remarkably lowering a vacuum degree of the vacuum space part 50.

When a porous material is provided inside the vacuum space part 50, porous material conduction heat {circle around (5)} may be a sum of the supporter conduction heat {circle around (2)} and the radiation transfer heat {circle around (4)}. The porous material conduction heat {circle around (5)} may be changed depending on various variables including a kind, an amount, and the like of the porous material.

According to an embodiment, a temperature difference ΔT₁ between a geometric center formed by adjacent bars 31 and a point at which each of the bars 31 is located may be preferably provided to be less than 0.5° C. Also, a temperature difference ΔT₂ between the geometric center formed by the adjacent bars 31 and an edge portion of the vacuum adiabatic body may be preferably provided to be less than 0.5° C. In the second plate member 20, a temperature difference between an average temperature of the second plate and a temperature at a point at which a heat transfer path passing through the conductive resistance sheet 60 or 63 meets the second plate may be largest. For example, when the second space is a region hotter than the first space, the temperature at the point at which the heat transfer path passing through the conductive resistance sheet meets the second plate member becomes lowest. Similarly, when the second space is a region colder than the first space, the temperature at the point at which the heat transfer path passing through the conductive resistance sheet meets the second plate member becomes highest.

This means that the amount of heat transferred through other points except the surface conduction heat passing through the conductive resistance sheet should be controlled, and the entire heat transfer amount satisfying the vacuum adiabatic body can be achieved only when the surface conduction heat occupies the largest heat transfer amount. To this end, a temperature variation of the conductive resistance sheet may be controlled to be larger than that of the plate member.

Physical characteristics of the parts constituting the vacuum adiabatic body will be described. In the vacuum adiabatic body, a force by vacuum pressure is applied to all of the parts. Therefore, a material having a strength (N/m²) of a certain level may be preferably used.

Under such circumferences, the plate members 10 and 20 and the side frame 70 may be preferably made of a material having a sufficient strength with which they are not damaged by even vacuum pressure. For example, when the number of bars 31 is decreased so as to limit the support conduction heat, deformation of the plate member occurs due to the vacuum pressure, which may be a bad influence on the external appearance of refrigerator. The radiation resistance sheet 32 may be preferably made of a material that has a low emissivity and can be easily subjected to thin film processing. Also, the radiation resistance sheet 32 is to ensure a strength high enough not to be deformed by an external impact. The supporting unit 30 is provided with a strength high enough to support the force by the vacuum pressure and endure an external impact, and is to have machinability. The conductive resistance sheet 60 may be preferably made of a material that has a thin plate shape and can endure the vacuum pressure.

In an embodiment, the plate member, the side frame, and the conductive resistance sheet may be made of stainless materials having the same strength. The radiation resistance sheet may be made of aluminum having a weaker strength that the stainless materials. The supporting unit may be made of resin having a weaker strength than the aluminum.

Unlike the strength from the point of view of materials, analysis from the point of view of stiffness is required. The stiffness (N/m) is a property that would not be easily deformed. Although the same material is used, its stiffness may be changed depending on its shape. The conductive resistance sheets 60 or 63 may be made of a material having a strength, but the stiffness of the material is preferably low so as to increase heat resistance and minimize radiation heat as the conductive resistance sheet is uniformly spread without any roughness when the vacuum pressure is applied. The radiation resistance sheet 32 requires a stiffness of a certain level so as not to contact another part due to deformation. Particularly, an edge portion of the radiation resistance sheet may generate conduction heat due to drooping caused by the self-load of the radiation resistance sheet. Therefore, a stiffness of a certain level is required. The supporting unit 30 requires a stiffness high enough to endure a compressive stress from the plate member and an external impact.

In an embodiment, the plate member and the side frame may preferably have the highest stiffness so as to prevent deformation caused by the vacuum pressure. The supporting unit, particularly, the bar may preferably have the second highest stiffness. The radiation resistance sheet may preferably have a stiffness that is lower than that of the supporting unit but higher than that of the conductive resistance sheet. The conductive resistance sheet may be preferably made of a material that is easily deformed by the vacuum pressure and has the lowest stiffness.

Even when the porous material 33 is filled in the vacuum space part 50, the conductive resistance sheet may preferably have the lowest stiffness, and the plate member and the side frame may preferably have the highest stiffness.

FIG. 5 is a view illustrating in detail a vacuum adiabatic body according to an embodiment. The embodiment proposed in FIG. 5 may be preferably applied to the door-side vacuum adiabatic body, and the description of the vacuum adiabatic body shown in FIG. 4 b among the vacuum adiabatic bodies shown in FIG. 4 may be applied to portions to which specific descriptions are not provided.

Referring to FIG. 5 , both end portions of the vacuum adiabatic body is heat-insulated by a separate product made of, for example, foaming urethane or Styrofoam, and an inside, i.e., a middle portion of the vacuum adiabatic body is heat-insulated in a vacuum state. The vacuum adiabatic body of this embodiment includes a first plate member 10 providing a wall for a low-temperature space, a second plate member 20 providing a wall for a high-temperature space, and a vacuum space part 50 defined as a gap part (gap or space) between the first plate member 10 and the second plate member 20. Also, the vacuum adiabatic body includes a conductive resistance sheet 60 for blocking heat conduction between the first and second plate members 10 and 20. Also, the vacuum adiabatic body includes a side frame 70 fastened to the conductive resistance sheet 60 and the second plate member 20 to provide a wall for one portion of the vacuum space part 50. Fastening parts of the side frame 70 may be formed through welding. A supporting unit 30 capable of maintaining a gap of the vacuum space part 50 may be provided inside the vacuum space part 50.

A peripheral adiabatic part (or peripheral adiabatic mold) 90 is provided at a peripheral portion, i.e., an outer edge portion of the vacuum adiabatic body, to improve the adiabatic performance of the edge portion of the vacuum adiabatic body, which is weak to heat insulation. The peripheral adiabatic part 90 includes at least an outer surface of the conductive resistance sheet 60, thereby providing an adiabatic effect. Accordingly, an inner surface of the conductive resistance sheet 60 can be heat-insulated by the vacuum space part 50, and the outer surface of the conductive resistance sheet 50 can be heat-insulated by the peripheral adiabatic part 90. As already described above, a sudden change in temperature occurs in the conductive resistance sheet 60, and hence it is further required to reduce adiabatic loss through the outer surface of the conductive resistance sheet 60.

The adiabatic performance of the peripheral adiabatic part 90 may be improved by a separate adiabatic member made of, for example, foaming urethane or Styrofoam. An inner panel 85 may provide a boundary to an inner portion of the peripheral adiabatic part 90. A separate structure may be added to allow the inner panel 85 to be fixed to the second plate member 20. The inner panel 85 can protect not only the boundary of the peripheral adiabatic part 90 but also an inner portion of the vacuum adiabatic body.

The peripheral adiabatic part 90 may be placed in a region defined as an inside of the inner panel 85, the second plate member 20, the side frame 70, the conductive resistance sheet 60, and the first plate member 10. A groove 79 (or recess) may be provided at an edge of the inner panel 85, and a gasket 80 may be fixed into the groove 79.

The gasket 80 is a part that enables the first space to be heat-insulated from a second space, and temperatures of both the first and second spaces with respect to the gasket 80 may be different from each other. Similarly, temperatures of both left and right sides of the inner panel 85 with respect to the gasket 80 may be different from each other. This has influence on a change in temperature of an inside of the peripheral adiabatic part 90 and adiabatic performance due to the change in temperature, in addition to that temperatures of both left and right sides of the conductive resistance sheet 60 are different from each other. Isothermal lines inside the peripheral adiabatic body 90 preferably have intervals as equal as possible so as to resist heat transfer through the inside of the peripheral adiabatic part 90.

In order to obtain such an effect, a place at which the gasket 80 is located and a place at which the conductive resistance sheet 60 is located are preferably opposite to each other in the vertical direction with the peripheral adiabatic part 90 interposed therebetween. According to the above-described configuration, the isothermal lines passing through the peripheral adiabatic part 90 can be provided at relatively equal intervals.

More accurately, at least one portion of the conductive resistance sheet 60 may be disposed inside a projection region in which projection is performed toward a third space from the region in which the gasket 80 is provided. For example, as illustrated in FIG. 5 , a projection or protrusion is formed on the inner panel 85 to accommodate the gasket. The projection may protrude toward the vacuum space formed by the first and second plate members 10, 20. Also, the conductive resistance sheet 60 may be disposed at a place biased to an edge of the vacuum adiabatic body from the projection region. For example, as illustrated in FIG. 5 , the conductive resistance sheet 60 vertically overlaps the projection, while being biased toward an outside portion of the protrusion (e.g., toward the outer edge). Accordingly, a path of heat transfer can be lengthened, so that the adiabatic efficiency of the vacuum adiabatic body can be further improved.

FIG. 6 illustrates temperature distribution curves with respect to positions of the conductive resistance sheet. FIG. 6(a) illustrates a case where the conductive resistance sheet is located biased to an inner direction of the vacuum adiabatic body while being located in the projection region. FIG. 6(b) illustrates a case where the conductive resistance sheet is placed in the first space. FIG. 6(c) illustrates a case where the conductive resistance sheet is located biased to the edge pf the vacuum adiabatic body while being located in the projection region. FIG. 6(d) illustrates a case where the conductive resistance sheet is located biased to the inside of the vacuum adiabatic body while being out of the projection region.

Paths of heat transfer will be described in detail with reference to FIG. 6 .

In the case of FIG. 6(b), heat infiltration into the conductive resistance sheet is severe, and therefore, degradation of adiabatic performance is severe. In the case of FIG. 6(b), reduction in adiabatic loss through a region out of the first space to reach the conductive resistance sheet as one portion of the first plate member 10 and infiltration of cold air into the peripheral adiabatic part 90 are severe, which is not preferable.

When comparing the cases of FIGS. 6(a) and 6(c), a path of heat transfer, considered using a vertical line of isothermal lines, is lengthened in the case of FIG. 6(c). In other words, the path of heat transfer is represented as a path of an upwardly convex parabola. Thus, the path of heat transfer can be lengthened. On the other hand, in the case of FIG. 6(a), only a path of heat transfer provides only a path in one direction such as a right upward direction or a left upward direction.

Thus, the path of heat transfer is further lengthened in the case of FIG. 6 , thereby obtaining an increase in adiabatic effect. However, the adiabatic performance may be changed through various modifications of designs, numerical values, and the like.

Referring back to FIG. 5 , the side frame 70 is provided at the outside of the conductive resistance sheet 60. The side frame 70 includes a first fastening part (or first portion/section) 74 as a part fastened to the conductive resistance sheet 60, a gap part (or second portion/section or connection wall) 73 extending downward from the first fastening part 74, i.e., toward the second plate member 20, and an extending part (or third portion/section) 72 bent from the gap part 73 to extend outward along an inner surface of the second plate member 20. An end portion of the extending part 72 may extend up to an edge of a front portion of the vacuum adiabatic body, and a second fastening part (or seal, joint, weld) 71 of the extending part 72 may be fastened to the second plate member 20 at the end portion of the extending part 72.

The second fastening part 71 may be provided through welding so as to maintain its sealing performance. In this case, a small deformation may occur in the second plate member 20 due to high-temperature heat generated in the welding. However, the second fastening part 71 is not provided at a front portion of the second plate member 20 but provided at an edge of the front portion or a side portion of the second plate member 20. Hence, the second fastening part 71 is not viewed by a user. In addition, formation of dews may occur on an outer surface of the second plate member 20, corresponding to the second fastening part 71, due to a difference in temperature between the end portion of the extending part 72 and the second plate member 20. The formation of dew may occur when the second space is in a state of high temperature and high humidity and the first space is in a state of low temperature. However, since the second fastening part 71 is not provided at the front portion of the second plate member 20 but provided at the edge of the front portion or the side portion of the second plate member 20, the formation of dew is not visible to the user. Thus, any separate member for covering the outer surface of the second plate member 20 is not required.

The extending part 72 extends along the inner surface of the second plate member 20. The extending part 72 may at least partially contact the second plate member 20 to reinforce the strength of an outer wall of the vacuum adiabatic body. Thus, it is possible to prevent deformation of the outer surface of the vacuum adiabatic body and to increase the flatness of the outer surface.

FIG. 7 is an exploded perspective view of a vacuum adiabatic body according to an embodiment.

Referring to FIG. 7 , there is provided a vacuum adiabatic assembly 21 including a first plate member 10 and a second plate member 20. A gap part between the first plate member 10 and the second plate member 20 forms a vacuum space part 50. The first plate member 10 is provided at one portion of an inner surface of the second plate member 20, and a region in which the first plate member 10 is not provided may be heat-insulated by a peripheral adiabatic part 90. A getter port 41 may be provided at a predetermined position of the first plate member 10. A side frame 70 may extend up to an outer circumferential portion of the second plate member 20 by an extending part 72. A second fastening part 71 is provided at an end portion of the extending part 72.

An inner panel 85 is provided inside the peripheral adiabatic part 90, and a basket 86 is mounted to be supported to the inner panel 85 or another product. The basket 86 may be provided to be larger as the vacuum adiabatic body is provided.

Referring to a view comparing performances, proposed in FIG. 12 , it can be seen that as the vacuum adiabatic body is provided, a width of the basket 86 is increased from W1 to W2. Accordingly, the internal volume of the refrigerator can be increased. The view proposed in FIG. 12 illustrates a door-in-door refrigerator in which storage goods can be obtained without opening the entire internal space of the refrigerator. In other words, the view proposed in FIG. 12 illustrates a case where the vacuum adiabatic body is used as an outer door of the refrigerator. In this case, the volume of storage goods that can be stored through the outer door can be increased, so that user's convenience can be further improved.

Referring back to FIG. 7 , a gasket 80 coupled to the inner panel 85 is provided, and a latch 88 capable of changing a lock state of the door may be further provided. The latch 88 may be fixed to an inside of the peripheral adiabatic part 90. In addition, an upper hinge 87 and a lower hinge 86 are fixed to the inner panel 85, and an upper cover 83 and a lower cover 81 may be provided to protect upper and lower sides of the vacuum adiabatic body, respectively.

According to this embodiment, after the vacuum adiabatic assembly 21 is manufactured, the vacuum adiabatic body can be produced using production equipment using the typical foaming urethane as it is. In other words, the door of the refrigerator, provided as the vacuum adiabatic body, can be manufactured using the existing refrigerator manufacturing equipment as it is.

Also, various parts required to operate the door can be conveniently mounted to the peripheral adiabatic part 90 and the inner panel 85 covering the peripheral adiabatic part 90.

Also, as the side frame 70 extends up to the edge of the second plate member 20, the strength of the vacuum adiabatic assembly 21 can be reinforced, so that the vacuum adiabatic body can be stably used even when various additions are further provided.

In addition, no formation of dews or no welding line is viewed by the user, so that a high-quality product can be provided. Furthermore, the internal volume of the door can be increased by the effect of the vacuum space part 50 placed between the first plate member and the second plate member.

Hereinafter, a vacuum pressure preferably determined depending on an internal state of the vacuum adiabatic body. As already described above, a vacuum pressure is to be maintained inside the vacuum adiabatic body so as to reduce heat transfer. At this time, it will be easily expected that the vacuum pressure is preferably maintained as low as possible so as to reduce the heat transfer.

The vacuum space part may resist the heat transfer by applying only the supporting unit 30. Alternatively, the porous material 33 may be filled together with the supporting unit in the vacuum space part 50 to resist the heat transfer. Alternatively, the vacuum space part may resist the heat transfer not by applying the supporting unit but by applying the porous material 33.

The case where only the supporting unit is applied will be described.

FIG. 8 illustrates graphs showing changes in adiabatic performance and changes in gas conductivity with respect to vacuum pressures by applying a simulation.

Referring to FIG. 8 , it can be seen that, as the vacuum pressure is decreased, i.e., as the vacuum degree is increased, a heat load in the case of only the main body (Graph 1) or in the case where the main body and the door are joined together (Graph 2) is decreased as compared with that in the case of the typical product formed by foaming polyurethane, thereby improving the adiabatic performance. However, it can be seen that the degree of improvement of the adiabatic performance is gradually lowered. Also, it can be seen that, as the vacuum pressure is decreased, the gas conductivity (Graph 3) is decreased. However, it can be seen that, although the vacuum pressure is decreased, the ratio at which the adiabatic performance and the gas conductivity are improved is gradually lowered. Therefore, it is preferable that the vacuum pressure is decreased as low as possible. However, it takes long time to obtain excessive vacuum pressure, and much cost is consumed due to excessive use of a getter. In the embodiment, an optimal vacuum pressure is proposed from the above-described point of view.

FIG. 9 illustrates graphs obtained by observing, over time and pressure, a process of exhausting the interior of the vacuum adiabatic body when the supporting unit is used.

Referring to FIG. 9 , in order to create the vacuum space part 50 to be in the vacuum state, a gas in the vacuum space part 50 is exhausted by a vacuum pump while evaporating a latent gas remaining in the parts of the vacuum space part 50 through baking. However, if the vacuum pressure reaches a certain level or more, there exists a point at which the level of the vacuum pressure is not increased any more (Δt1). After that, the getter is activated by disconnecting the vacuum space part 50 from the vacuum pump and applying heat to the vacuum space part 50 (Δt2). If the getter is activated, the pressure in the vacuum space part 50 is decreased for a certain period of time, but then normalized to maintain a vacuum pressure of a certain level. The vacuum pressure that maintains the certain level after the activation of the getter is approximately 1.8×10⁻⁶ Torr.

In the embodiment, a point at which the vacuum pressure is not substantially decreased any more even though the gas is exhausted by operating the vacuum pump is set to the lowest limit of the vacuum pressure used in the vacuum adiabatic body, thereby setting the minimum internal pressure of the vacuum space part 50 to 1.8×10⁻⁶ Torr.

FIG. 10 illustrates graphs obtained by comparing vacuum pressures and gas conductivities.

Referring to FIG. 10 , gas conductivities with respect to vacuum pressures depending on sizes of a gap in the vacuum space part 50 are represented as graphs of effective heat transfer coefficients (eK). Effective heat transfer coefficients (eK) were measured when the gap in the vacuum space part 50 has three sizes of 2.76 mm, 6.5 mm, and 12.5 mm. The gap in the vacuum space part 50 is defined as follows. When the radiation resistance sheet 32 exists inside vacuum space part 50, the gap is a distance between the radiation resistance sheet 32 and the plate member adjacent thereto. When the radiation resistance sheet 32 does not exist inside vacuum space part 50, the gap is a distance between the first and second plate members.

It can be seen that, since the size of the gap is small at a point corresponding to a typical effective heat transfer coefficient of 0.0196 W/mK, which is provided to a adiabatic material formed by foaming polyurethane, the vacuum pressure is 2.65×10⁻¹ Torr even when the size of the gap is 2.76 mm. Meanwhile, it can be seen that the point at which reduction in adiabatic effect caused by gas conduction heat is saturated even though the vacuum pressure is decreased is a point at which the vacuum pressure is approximately 4.5×10⁻³ Torr. The vacuum pressure of 4.5×10⁻³ Torr can be defined as the point at which the reduction in adiabatic effect caused by gas conduction heat is saturated. Also, when the effective heat transfer coefficient is 0.1 W/mK, the vacuum pressure is 1.2×10⁻² Torr.

When the vacuum space part 50 is not provided with the supporting unit but provided with the porous material, the size of the gap ranges from a few micrometers to a few hundreds of micrometers. In this case, the amount of radiation heat transfer is small due to the porous material even when the vacuum pressure is relatively high, i.e., when the vacuum degree is low. Therefore, an appropriate vacuum pump is used to adjust the vacuum pressure. The vacuum pressure appropriate to the corresponding vacuum pump is approximately 2.0×10⁻⁴ Torr. Also, the vacuum pressure at the point at which the reduction in adiabatic effect caused by gas conduction heat is saturated is approximately 4.7×10⁻² Torr. Also, the pressure where the reduction in adiabatic effect caused by gas conduction heat reaches the typical effective heat transfer coefficient of 0.0196 W/mK is 730 Torr.

When the supporting unit and the porous material are provided together in the vacuum space part, a vacuum pressure may be created and used, which is middle between the vacuum pressure when only the supporting unit is used and the vacuum pressure when only the porous material is used.

FIG. 11 is a partial sectional view of a vacuum adiabatic body according to an embodiment.

The embodiment proposed in FIG. 11 is identical to the embodiment proposed in FIG. 5 , except that a conductive resistance adiabatic material 91 (or conductive resistance adiabatic insulator or sheet) is provided to further reduce heat loss through an outer surface of a conductive resistance sheet 60. The conductive resistance adiabatic material 91 may be provided to cover at least one portion of a side frame 70 and at least one portion of a first plate member 10 together with the conductive resistance sheet 60. Thus, it is possible to further reduce heat conducted along the first plate member 10. When the conductive resistance adiabatic material 91 is provided, any peripheral adiabatic part 90 may not be additionally provided. However, as the peripheral adiabatic part 90 is provided, adiabatic efficiency can be further improved, which is preferable.

Meanwhile, the conductive resistance adiabatic material 91 may further extend toward a first space while being out of the position at which the peripheral adiabatic part 90. Accordingly, it is possible to further reduce heat or cold air transferred to the conductive resistance sheet 60 along the first plate member 10.

In the description of the present disclosure, a part for performing the same action in each embodiment of the vacuum adiabatic body may be applied to another embodiment by properly changing the shape or dimension of the another embodiment. Accordingly, still another embodiment can be easily proposed. For example, in the detailed description, in the case of a vacuum adiabatic body suitable as a door-side vacuum adiabatic body, the vacuum adiabatic body may be applied as a main body-side vacuum adiabatic body by properly changing the shape and configuration of a vacuum adiabatic body.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

The vacuum adiabatic body proposed in the present disclosure may be preferably applied to refrigerators. However, the application of the vacuum adiabatic body is not limited to the refrigerators, and may be applied in various apparatuses such as cryogenic refrigerating apparatuses, heating apparatuses, and ventilation apparatuses.

According to the present disclosure, the vacuum adiabatic body can be industrially applied to various adiabatic apparatuses. The adiabatic effect can be enhanced, so that it is possible to improve energy use efficiency and to increase the effective volume of an apparatus.

However, it is difficult to obtain an adiabatic effect of a practical level by providing the walls of the refrigerator to be in a sufficient vacuum state. Specifically, it is difficult to prevent heat transfer at a contact portion between external and internal cases having different temperatures. Further, it is difficult to maintain a stable vacuum state. Furthermore, it is difficult to prevent deformation of the cases due to a sound pressure in the vacuum state. Due to these problems, the technique of Reference Document 3 is limited to cryogenic refrigerating apparatuses, and is not applied to refrigerating apparatuses used in general households.

Embodiments provide a vacuum adiabatic body and a refrigerator, which can obtain a sufficient adiabatic effect in a vacuum state and be applied commercially.

In one embodiment, a vacuum adiabatic body includes: a first plate member defining at least one portion of a wall for a first space; a second plate member defining at least one portion of a wall for a second space having a different temperature from the first space; a sealing part sealing the first plate member and the second plate member to provide a third space that has a temperature between the temperature of the first space and the temperature of the second space and is in a vacuum state; a supporting unit maintaining the third space; a heat resistance unit at least including a conductive resistance sheet capable of resisting heat conduction flowing along a wall for the third space to decrease a heat transfer amount between the first plate member and the second plate member; and an exhaust port through which a gas in the third space is exhausted, wherein the vacuum adiabatic body further includes a side frame fastened to the conductive resistance sheet and the second plate member, and wherein the side frame is fastened to an edge portion of the second plate member.

The vacuum adiabatic body may include a conductive resistance adiabatic material at least heat-insulating an outer surface of the conductive resistance sheet, the conductive resistance adiabatic material heat-insulating at least one portion of the side frame and at least one portion of the first plate member.

The vacuum adiabatic body may include: a peripheral adiabatic part provided to an outer wall of an edge portion of the third space to improve the adiabatic performance of the edge portion of the third space; and a conductive resistance adiabatic material at least heat-insulating the outer surface of the conductive resistance sheet, the conductive resistance adiabatic material further extending toward the first space while being out of the peripheral adiabatic part.

The side frame may include: a first fastening part fastened to the conductive resistance sheet; a gap part bent from the first fastening part to extend in a gap direction of the second space; an extending part bent from the gap part to extend outward along an inner surface of the second plate member; and a second fastening part fastened to the second plate member. At least one portion of the extending part may contact the inner surface of the second plate member. A height of the gap part may be equal to that of the third space. Each of the first and second fastening parts may be provided as a welding part.

The vacuum adiabatic body may include a peripheral adiabatic part provided at an outside of the outer wall of the edge portion of the third space to improve the adiabatic performance of the edge portion of the third space. A heat transfer path of the peripheral adiabatic part may be provided as a path of a parabola. The vacuum adiabatic body may further include: an inner panel for protecting at least one portion of the peripheral adiabatic part; and a gasket fixed to the inner panel. The conductive resistance sheet may be provided at the opposite side of the gasket with the peripheral adiabatic part interposed therebetween.

In another embodiment, a vacuum adiabatic body includes: a first plate member defining at least one portion of a wall for a first space; a second plate member defining at least one portion of a wall for a second space having a different temperature from the first space; a sealing part sealing the first plate member and the second plate member to provide a third space that has a temperature between the temperature of the first space and the temperature of the second space and is in a vacuum state; a supporting unit maintaining the third space; a heat resistance unit including at least one conductive resistance sheet to decrease a heat transfer amount between the first plate member and the second plate member, wherein the at least one conductive resistance sheet is thinner than each of the first and second plate members and provided as a curved surface to resist heat conduction flowing along a wall for the third space; and a side frame fastened to the conductive resistance sheet and the second plate member.

A change in temperature of the conductive resistance sheet may be more severe than that of each of the first and second plate members. The conductive resistance sheet may define, together with each of the first and second plate members, at least one portion of the wall for the third space, and have at least one curved part. The conductive resistance sheet may have a lower stiffness than each of the first and second plate members and the supporting unit. The vacuum adiabatic body may further include: a peripheral adiabatic part provided at an outside an edge portion of the third space to improve the adiabatic performance of the edge portion of the third space; an inner panel for protecting at least one portion of the peripheral adiabatic part; and a gasket fixed to the inner panel. The conductive resistance sheet may be provided at the opposite side of the gasket with the peripheral adiabatic part interposed therebetween. At least one portion of the conductive resistance sheet may be placed in a projection region in which projection is performed toward the third space from a region in which the gasket is provided. The conductive resistance sheet may be placed biased to an edge of the vacuum adiabatic body in the projection region.

A vacuum degree (or pressure) of the third space may be equal to or greater than 1.8×10⁻⁶ Torr and equal to or smaller than 4.5×10⁻³ Torr.

In still another embodiment, a refrigerator includes: a main body provided with an internal space in which storage goods are stored; and a door provided to open/close the main body from an external space, wherein, in order to supply a refrigerant into the main body, the refrigerator includes: a compressor for compressing the refrigerant; a condenser for condensing the compressed refrigerant; an expander for expanding the condensed refrigerant; and an evaporator for evaporating the expanded refrigerant to take heat, wherein the door includes a vacuum adiabatic body, wherein the vacuum adiabatic body includes: a first plate member defining at least one portion of a wall for the internal space; a second plate member defining at least one portion of a wall for the external space; a sealing part sealing the first plate member and the second plate member to provide a vacuum space part that has a temperature between a temperature of the internal space and a temperature of the external space and is in a vacuum state; a supporting unit maintaining the vacuum space part; a heat resistance unit at least including a conductive resistance sheet capable of resisting heat conduction flowing along a wall for the third space to decrease a heat transfer amount between the first plate member and the second plate member; and an exhaust port through which a gas in the vacuum space part is exhausted, wherein the vacuum adiabatic body further includes: a side frame fastened to the conductive resistance sheet and the second plate member; and a conductive resistance adiabatic material heat-insulating an outer surface of the conductive resistance sheet, at least one portion of the side frame, and at least one portion of the first plate member.

The refrigerator may include a peripheral adiabatic part provided to an outer wall of an edge portion of the vacuum space part to improve the adiabatic performance of the edge portion of the vacuum space part. The side frame may include: a first fastening part fastened to the conductive resistance sheet; a gap part bent from the first fastening part to extend in a gap direction of the second space; an extending part bent from the gap part to extend outward along an inner surface of the second plate member; and a second fastening part fastened to the second plate member. The side frame may be fastened to a side portion of the vacuum adiabatic body.

According to the present disclosure, it is possible to a sufficient vacuum adiabatic effect. According to the present disclosure, it is possible to prevent the formation of dews at the door and to improve the adiabatic performance of an edge portion of the vacuum adiabatic body. Also, it is possible to increase the internal accommodation volume of an outer door in a door-in-door refrigerator.

The details of one or more embodiments are set forth in the accompanying drawings and the description below. Other features will be apparent from the description and drawings, and from the claims.

Any reference in this specification to “one embodiment,” “an embodiment,” “example embodiment,” etc., means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of such phrases in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the purview of one skilled in the art to effect such feature, structure, or characteristic in connection with other ones of the embodiments.

Although embodiments have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art. 

What is claimed is:
 1. A vacuum adiabatic body comprising: a first plate configured to have a first temperature; a second plate configured to have a second temperature different than the first temperature; a seal configured to seal the first plate and the second plate to provide an inner space, and the inner space is to be provided in a vacuum state; a support provided in the inner space to maintain a gap in the inner space, in a first direction, between the first plate and the second plate; a thermal insulator configured to reduce heat transfer between the first plate and the second plate; a peripheral adiabatic part provided adjacent a distal end of the inner space to improve an adiabatic performance at the distal end of the inner space; an inner panel configured to protect at least one portion of the peripheral adiabatic part; and a gasket to attach to the inner panel, wherein the thermal insulator includes a conductive resistance sheet fixed to the first plate and configured to resist heat conduction along a wall adjacent the inner space to decrease heat transfer between the first plate and the second plate, and wherein the conductive resistance sheet is provided adjacent to the peripheral adiabatic part, and the conductive resistance sheet is aligned in the first direction to the gasket.
 2. The vacuum adiabatic body of claim 1, wherein a thickness of the conductive resistance sheet is less than a thickness of the second plate.
 3. The vacuum adiabatic body of claim 1, wherein a length between the conductive resistance sheet and the inner space is shorter than a length between the inner space and the inner panel.
 4. The vacuum adiabatic body of claim 1, wherein the conductive resistance sheet is coupled to the first plate, and is configured to resist heat conduction along the first plate adjacent the inner space to reduce heat transfer between the first plate and the second plate.
 5. The vacuum adiabatic body of claim 1, wherein the conductive resistance sheet is provided within a main portion of the inner space, and the conductive resistance sheet is spaced apart from a side portion of the inner space.
 6. The vacuum adiabatic body of claim 1, wherein the conductive resistance sheet is spaced apart from the first plate and the second plate.
 7. The vacuum adiabatic body of claim 1, wherein the conductive resistance sheet is provided within a main portion of the inner space, and the conductive resistance sheet is to extend into a side portion of the inner space.
 8. The vacuum adiabatic body of claim 1, wherein the conductive resistance sheet is provided at a main portion of the inner space without being provided in a side end portion of the inner space.
 9. The vacuum adiabatic body of claim 1, comprising a side frame connected to the conductive resistance sheet and an edge portion of the second plate.
 10. The vacuum adiabatic body of claim 9, wherein a thickness of the side frame is greater than a thickness of the conductive resistance sheet, and the side frame is made of metal.
 11. The vacuum adiabatic body of claim 1, wherein the inner panel has a protruding region that protrudes into the peripheral adiabatic part to accommodate the gasket, and the conductive resistance sheet is positioned such that at least a portion of the conductive resistance sheet spatially overlaps the protruding region of the inner panel in the first direction.
 12. A vacuum adiabatic body comprising: a first plate configured to have a first temperature; a second plate configured to have a second temperature different than the first temperature; a seal configured to seal the first plate and the second plate to provide an inner space, and the inner space is to be provided in a vacuum state; a support provided in the inner space to maintain a gap in the inner space, in a first direction, between the first plate and the second plate; a thermal insulator configured to reduce heat transfer between the first plate and the second plate; and a peripheral adiabatic part provided adjacent a distal end of the inner space to improve an adiabatic performance at the distal end of the inner space; wherein a heat transfer inside the peripheral adiabatic part is lengthened in the first direction based on a heat transfer path of an upwardly convex parabola.
 13. The vacuum adiabatic body of claim 12, wherein the heat transfer path of the convex parabola is concave to the inner space.
 14. The vacuum adiabatic body of claim 12, comprising: an inner panel configured to protect at least one portion of the peripheral adiabatic part; and a gasket to attach to the inner panel, wherein the heat transfer path of the convex parabola is disposed between the inner space and the gasket.
 15. The vacuum adiabatic body of claim 14, wherein the heat transfer path of the convex parabola is convex to the gasket.
 16. The vacuum adiabatic body of claim 12, wherein the thermal insulator is provided adjacent to the peripheral adiabatic part and is positioned to correspond to a position of the heat transfer path of the convex parabola.
 17. A vacuum adiabatic body comprising: a first plate to be adjacent a first space, and configured to have a first temperature; a second plate to be adjacent a second space, and configured to have a second temperature different than the first temperature; a seal configured to seal the first plate and the second plate to provide an inner space, and the inner space is to be provided in a vacuum state; a support provided in the inner space to maintain a gap in the inner space, in a first direction, between the first plate and the second plate; and a thermal insulator configured to reduce heat transfer between the first plate and the second plate; and a gasket to enable the first space to be heat-insulated from the second space; wherein the thermal insulator includes a conductive resistance sheet fixed to the first plate and configured to resist heat conduction along a wall adjacent the inner space to decrease heat transfer between the first plate and the second plate, and wherein a projection region protrudes from the gasket toward the inner space in the first direction, and the conductive resistance sheet is positioned such that at least a portion of the conductive resistance sheet spatially overlaps the projection region in the first direction.
 18. The vacuum adiabatic body of claim 17, wherein the conductive resistance sheet is spatially aligned with the projection region in the first direction and is biased to an edge of the vacuum adiabatic body.
 19. The vacuum adiabatic body of claim 17, comprising: a peripheral adiabatic part provided adjacent a distal end of the inner space to improve an adiabatic performance at the distal end of the inner space; an inner panel configured to protect at least one portion of the peripheral adiabatic part, wherein the gasket is attached to the inner panel.
 20. A vacuum adiabatic body comprising: a first plate configured to have a first temperature; a second plate configured to have a second temperature different than the first temperature; a seal configured to seal the first plate and the second plate to provide an inner space, and the inner space is to be provided in a vacuum state; a support provided in the inner space to maintain a gap in the inner space, in a first direction, between the first plate and the second plate; a thermal insulator configured to reduce heat transfer between the first plate and the second plate; a peripheral adiabatic part provided adjacent a distal end of the inner space to improve an adiabatic performance at the distal end of the inner space; an inner panel configured to protect at least one portion of the peripheral adiabatic part; and a gasket to attach to the inner panel, wherein the thermal insulator includes a conductive resistance sheet fixed to the first plate and configured to resist heat conduction along a wall adjacent the inner space to decrease heat transfer between the first plate and the second plate, and wherein the conductive resistance sheet is provided adjacent to the peripheral adiabatic part, and the conductive resistance sheet is aligned in the first direction to the gasket.
 21. The vacuum adiabatic body of claim 20, wherein the inner panel has a region that protrudes into the peripheral adiabatic part to accommodate the gasket, and the conductive resistance sheet is positioned such that at least a portion of the conductive resistance sheet spatially overlaps, in the first direction, the region that protrudes into the peripheral adiabatic part.
 22. A vacuum adiabatic body comprising: a first plate configured to have a first temperature; a second plate configured to have a second temperature different than the first temperature; a seal configured to seal the first plate and the second plate to provide an inner space, and the inner space is to be provided in a vacuum state; a support provided in the inner space to maintain a gap in the inner space between the first plate and the second plate; a thermal insulator configured to reduce heat transfer between the first plate and the second plate; a peripheral adiabatic part provided adjacent a distal end of the inner space to improve an adiabatic performance at the distal end of the inner space; and a side frame connected to the conductive resistance sheet and the second plate, the side frame being connected to an edge portion of the second plate, wherein the side frame includes: a first portion connected to the conductive resistance sheet; a second portion bent from the first portion to extend in a gap between the first and second plates toward the second plate; a third portion bent from the second portion to extend outward along an inner surface of the second plate, and a surface of the third portion directly contacting the inner surface of the second plate; and a seal between the third portion and the second plate.
 23. A vacuum adiabatic body comprising: a first plate configured to have a first temperature; a second plate configured to have a second temperature different than the first temperature; a seal configured to seal the first plate and the second plate to provide an inner space, and the inner space is to be provided in a vacuum state; a support provided in the inner space to maintain a gap in the inner space between the first plate and the second plate; a thermal insulator configured to reduce heat transfer between the first plate and the second plate; and a peripheral adiabatic part provided adjacent a distal end of the inner space to improve an adiabatic performance at the distal end of the inner space, wherein the thermal insulator includes a conductive resistance sheet fixed to the first plate and configured to resist heat conduction along a wall adjacent the inner space to decrease heat transfer between the first plate and the second plate, and wherein the vacuum adiabatic body comprises a conductive resistance adiabatic material provided over an outer surface of the conductive resistance sheet, the conductive resistance adiabatic material being positioned to thermally insulate at least one portion of the first plate.
 24. A vacuum adiabatic body comprising: a first plate configured to have a first temperature; a second plate configured to have a second temperature different than the first temperature; a seal configured to seal the first plate and the second plate to provide an inner space, and the inner space is to be provided in a vacuum state; a support provided in the inner space to maintain a gap in the inner space between the first plate and the second plate; a thermal insulator configured to reduce heat transfer between the first plate and the second plate; and a peripheral adiabatic part provided adjacent a distal end of the inner space to improve an adiabatic performance at the distal end of the inner space, wherein the thermal insulator includes a conductive resistance sheet fixed to the first plate and configured to resist heat conduction along a wall adjacent the inner space to decrease heat transfer between the first plate and the second plate, and wherein the thermal insulator includes a conductive resistance adiabatic material provided over an outer surface of the conductive resistance sheet, wherein at least a portion of the conductive resistance adiabatic material extends toward the first plate and away from the peripheral adiabatic part. 